X25AM Programming Manual

ITI Applications
X25AM Programming Manual—527201-001
2-5
Exchanging Data
READ Request
WRITEREAD Request
Data blocks beginning with STX or SOH should be received. If an ACK (instead of data
blocks) is received during the READ phase, the WRITEREAD terminates with error
172 (I/O protocol violation detected).
CONVERSATION MODE With a READ request, conversation mode is used to
read data entered at the terminal.
PAGE MODE With a READ request, page mode is used to retrieve
the value of a function key pressed at the terminal
keyboard. The terminal keyboard is locked and a
specifically formatted message containing the value
of the function key is transmitted.
The terminal does not transmit data unless solicited
to do so. ITI performs the solicitation when your
application makes a READ request.
CONVERSATION MODE With a WRITEREAD request, conversation mode is
used to write a prompt to the terminal and to read
the response.
PAGE MODE With a WRITEREAD request, page mode is used to
send escape sequences that require the terminal to
respond by returning a specific type of data. The file-
system buffer must initially contain only the escape
code.
Table 2-3. Escape Codes for Page Mode Input/Output Operations
Code Operation Terminal Transmits
ESC< Read buffer Entire page
ESC= Read with address Specified part of page
ESC] Read with address all All fields
ESC^ Read terminal status Terminal status
ESCa Read cursor address Current cursor line/column